Aqueous metalworking fluids have long been established in the art and used in metalworking processes such as rolling, stamping, drawing, cutting, and extruding. Such fluids lubricate and cool the metal during the working process and this promotes long tool life which aids in increased production and the attainment of high quality finished metal products. Many attempts have been made to provide useful lubricant compositions which are either oil based or aqueous based fluids as disclosed in U.S. Pat. Nos. 4,075,393; 4,108,785; 4,132,662; 4,149,983; 4,151,099; 4,153,464; 4,160,370; 4,172,802; and 4,178,260.
The above patents represent a number of approaches that have been taken by the metalworking industry in an attempt to provide good lubricating and anti-wear properties in metalworking libricant compositions, and to minimize other problems such as water staining of sensitive non-ferrous metals and alloys. Lubricants are employed in cold rolling or sheet metalworking processes to prevent damage to the surface of the metal and to facilitate the operation. For instance, when cold rolling aluminum and other sensitive metals, oil based lubricants are employed to insure sheets of uniform thickness and undesirable surface defects. An ideal lubricant for the cold rolling of aluminum and other sensitive non-ferrous alloys would be a water active product in an aqueous system. This would have a cooling effect during the rolling operation thereby allowing an increase in mill speed. However, aluminum and aluminum alloys are susceptible to water staining. The staining appears as blemishes on the surface of the metal and in some cases pitting occurs. In addition to creating an appearance problem the staining interferes with subsequent operations such as drawing, stamping, cutting, and so forth.
It would be highly advantageous if aqueous metalworking lubricant compositions were available, particularly for use in the cold rolling of aluminum and other sensitive non-ferrous alloys to provide proper lubrication but without water staining.